he edentulous patient has not disappeared.
While the prevalence of edentulism is less
than what it was 20 years ago, about 33 percent of Americans older than 65 years of age
were completely edentulous as of 2000.1,2
When all Americans older than 18 years of age are considered, approximately 10 percent are completely
without teeth.1 There are disparities in
the rate of edentulism among racial and
When planning ethnic groups, with Mexican-Americans
treatment for least likely to lose all of their teeth.1
patients with Edentulism is one of a few dental condiedentulous tions for which state-specific data exist.
These data reveal a wide variation in
mandibles,
the percentages of the population aged
clinicians 65 and older who have no teeth, from a
should consider low of 13.9 percent in Hawaii to a high
the implant- of 47.9 percent in West Virginia.2
The classical treatment plan for the
supported
edentulous
patient is the complete
prosthesis.
removable maxillary and mandibular
denture. This treatment is relatively
inexpensive in comparison with fixed implant-supported
prostheses, but it has several drawbacks (Box 1). Like all
dental restorative procedures, a complete removable denture requires extensive attention to detail if an excellent
clinical result is to be achieved. Depending on the shape
of the regional ridge, the denture may be unstable or
inadequately retained, leaving the patient dissatisfied

The implant-supported
overdenture as an
alternative to the
complete mandibular
denture

Background. Approximately one-third
of Americans older than 65
years of age are fully edenA D A
J
tulous, requiring replace✷
✷

ment of missing teeth.
While the conventional
denture may meet the
N
C
needs of many patients,
A UING EDU 1
R
TICLE
others require more
retention, stability, function and
esthetics, especially in the mandible. The
implant-supported prosthesis is an alternative to the conventional removable denture.
Methods. This article describes the
strengths of the implant-supported
mandibular overdenture. The authors also
outline the risks of this approach. They performed a review of recent literature to summarize the reported success rate of
implants used to support a mandibular
overdenture.
Results. The literature review indicates
that implants placed in the anterior
mandible (anterior to the foramen) have a
success rate better than 95 percent.
Patients have reported a high degree of
satisfaction with the implant-supported
overdenture.
Conclusions. The literature indicates
that implant-supported overdentures in the
mandible provide predictable results with
improved stability, retention, function and
patient satisfaction compared with conventional dentures. Implants placed in the
anterior mandible have a success rate equal
to or greater than 95 percent.
Clinical Implications. When planning
treatment for patients with edentulous
mandibles, clinicians should consider the
implant-supported prosthesis.

IO
N

COVER STORY

ABSTRACT

T

& R E S T O R AT I V E C A R E

A

COSMETIC

with the functional result.
The rate of residual ridge resorption
in edentulous patients who do not have
tooth replacements is highly variable
and may be as much as several millimeters per year. This resorption can
render the current prosthesis inadequate in terms of both function and
esthetics and can lead to the necessity
of fabricating a new denture. Over time,

denture (Figure 2) has good stability and retention, and patients
DISADVANTAGES OF THE COMPLETE
who have received them have
REMOVABLE DENTURE.
reported improved function and
satisfaction.3
dExtensive detail required for proper fabrication
Another benefit of implantdLack of stability (especially in mandible)
dLack of retention (especially in mandible)
supported prostheses is suggested
dContinued loss of alveolar bone leading to further instability and lack
by preliminary data indicating
of retention
that after receiving implants,
dPatients using such dentures may be led to believe professional dental
care no longer is needed
patients may eat a diet with more
dLack of chewing function when ill-fitting
fiber (M.K. Jeffcoat, D.M.D.,
dSocial concerns (slippage, unnatural appearance)
unpublished data, 2003). If this is
proven, the implant-supported
BOX 2
denture would make an important
contribution to general health and
ADVANTAGES OF THE IMPLANT-SUPPORTED
well-being.
OVERDENTURE.
Other studies have measured
the
rate of residual ridge resorpdAs few as two to four implants may be used for support
tion
in the five years after implant
dGood stability
dGood retention
placement. The rate of resorption
dImproved function
is decreased significantly from the
dImproved esthetics
rates seen with conventional dendReduced residual ridge resorption
dSimplest implant-supported prosthesis
tures, and recent research has
dPossible incorporation of existing denture into the new prosthesis
shown that the height of the posterior ridge increases with continued use of implant-supported prostheses.4
occlusion, esthetics and function may be
compromised.
Although patients in studies are not directly comPerhaps one of the greatest drawbacks to the
parable to the population as a whole, patients
full denture is the misconception to which it gives
with implant-supported prostheses return for
rise, on the patient’s part, that dental care no
visits with the same practitioner at a very high
longer is needed. Such patients deny themselves
rate.5 In one study, this rate exceeded 95 percent
not only routine maintenance of their prostheses
over seven years, permitting detection of two canbut also the advantages of cancer screening.
cers in a study population of 120.5 A 2002 conToday’s patients have high expectations for
sensus statement developed by scientists and
oral health; providing a traditional denture that
expert clinicians at a symposium on the efficacy of
eventually becomes an ill-fitting prosthesis does
overdentures for the treatment of edentulous
not help meet these expectations. The implantpatients held at McGill University in Montreal,
supported denture is one solution to these
Quebec, Canada, lists a mandibular overdenture
problems.
as the first choice in treating edentulous
patients.6
ADVANTAGES OF THE IMPLANTSuccess rates. Implants no longer are considSUPPORTED PROSTHESIS
ered experimental. The table shows representaThe implant-supported overdenture has many
tive clinical trials over the past six years.3,5,7-13 We
advantages. Although as few as two to four
performed a library search for implant clinical
implants may be used for support (Box 2), it is
trials in the anterior mandible reported in
beneficial to use more than two implants in the
English; the table shows the primary author, size
unlikely event that one of the implants fails to
of study, study design and representative results
function during the patient’s life span. Implant
of each study we found. (This article is not
placement surgery is relatively simple to perform
intended to provide extensive statistical metaand, in experienced hands, may take less than an
analysis.) Most of the trials were longitudinal
hour. Many options are available for retention of
studies of cohorts of patients treated according to
the prosthesis, including magnets, clips, bars and
the sample protocol. We evaluated data from
balls (Figure 1). The resultant implant-supported
these studies and found that they demonstrate a
1456

Figure 2. The clinical results of the implant placement
shown in Figure 1: an implant-supported mandibular
denture and a conventional maxillary denture.

TABLE

associated with
REPRESENTATIVE IMPLANT CLINICAL TRIAL RESULTS. implant placement are
outlined in Box 3.14,15
TYPE OF STUDY
RESULT
AUTHOR
Risks include postop3
erative bleeding,
Higher patient satisfaction
Awad and colleagues
Randomized Clinical
than with conventional
Trial
numbness if the
denture
mandibular nerve is
Buser and colleagues7
Survival rate: > 95 percent
disturbed, infection
for screws
Prospective
and lack of osseointeTawse-Smith and
Success rate: 95.8 percent
gration. The risks can
colleagues8
Prospective
be minimized with
Meijer and colleagues9
Success rate: 97 percent
Prospective, Multicenter
proper training and
10
experience. Case
Moberg and colleagues
Success rate: submerged
Prospective
implants, 97.9 percent;
selection and diagnonsubmerged implants, 96.8
nosis is the key to sucpercent
cess with implant proRodriguez and
Success rate: 92.6 percent
Prospective, Multicenter
11
cedures, as with all
colleagues
dental procedures.
Morris and Ochi12
Success rate: hydroxyapatite,
Prospective, Multicenter
Other risk factors
or HA, cylinder, 97.5 percent;
titanium, or Ti, screw, 99.4
also may affect the
percent
outcome of the
Jeffcoat and colleagues5
Success rate: HA, 99 percent;
Prospective, Multicenter
implant-supported
Ti screw, 96 percent
prosthesis. Smoking is
Bergendal and
Success rate: 100 percent
Prospective
a risk factor for longEngquist13
term implant success.
Patients who smoke
are more likely to experience infection and/or prosuccess rate above 95 percent in the anterior
gressive alveolar bone loss, which ultimately may
mandible. It is noteworthy that among the
lead to implant loss. A smoking cessation plan
sources of support for these studies were many
including periodic assessment of cotinine levels
different implant manufacturers and the U.S.
may be ordered to track long-term exposure to
government. Furthermore, the success rate
exceeds the rate prescribed for the ADA Seal of
tobacco.
Acceptance by the ADA Council on Scientific
Untreated periodontitis also is a risk factor for
Affairs.
the failure of dental implants. Obviously, fully
Risks. No surgical procedure, including the
edentulous patients do not have periodontitis, but
placement of implants, is without risk. The risks
even after the extraction of a single tooth with
JADA, Vol. 134, November 2003
Copyright ÂŠ2003 American Dental Association. All rights reserved.

1457

COSMETIC

& RESTORATIVE CARE

BOX 3

supported prostheses should be
considered in planning treatment
for the fully edentulous patient. ■

RISK FACTORS FOR FAILURE OF DENTAL
IMPLANTS.
dSmoking
dFactors that affect healing of bone (such as diabetes, use of steroids)
dUntreated periodontal disease
dAnatomy (if bone in recipient site is inadequate, grafting may be
necessary)

dPoor bone quality
dInadequate practitioner training, experience or both
dPatient compliance concerns
periodontal disease, the site may harbor
pathogenic bacteria that may lead to periimplantitis.
Factors that may influence the healing or
potential infection of the implant recipient site
also may affect the outcome. Uncontrolled diabetes and use of drugs such as steroids need to be
carefully considered in the treatment plan, and
the clinician may need to adjust time to loading
accordingly. Anatomy and bone quality also affect
the outcome and ease of surgical placement of
implants. Implants need adequate bone height
and width for placement. If the native bone at the
recipient site is inadequate to accept the implant,
bone grafts—with or without guided bone regeneration—must be considered. Bone quality, which
is related to density of the trabecular bone, usually is not a problem in the anterior mandible.
Other segments of the alveolar bone, such as the
posterior maxilla, are more likely to have lower
bone density, which can limit implant stability
and osseointegration.
With proper diagnosis and treatment planning,
the limitations and risks of implant placement
are manageable. Good communication between
the surgical and restorative members of the team
is a necessity. High-quality training and experience in implant surgery and restorative care are
fundamental to delivering quality care.
CONCLUSION

The literature and clinical experience indicate
that the implant-supported prosthesis provides
predictable results with improved stability and
function and a high degree of satisfaction as compared with conventional removable dentures.
Clinical studies in the literature in which
implants were used in the mandible anterior to
the foramen indicate that the success rate for
implants in the lower mandible is 95 percent or
greater. These data indicate that implant1458

Dr. Doundoulakis maintains a private practice
in cosmetic dental rehabilitation in New York
City. He also is section chief, Maxillofacial Prosthetics, and attending dentist, St. Luke’sRoosevelt Hospital Center, New York City; and
attending and assistant clinical professor, New
York/Presbyterian, The University Hospitals of
Columbia and Cornell, New York City. Address
reprint requests to Dr. Doundoulakis at 3 E. 66th
St., New York, N.Y. 10021, e-mail
“cosmeticdental@att.net”.